Chuck with torque indicator

ABSTRACT

A chuck for a driver having a rotatable drive shaft, the chuck having a cylindrical body member having a nose section and a tail section. A plurality of jaws is slidably positioned in the body, and each jaw has a jaw face and threads. A nut is rotatably mounted on the body in engagement with the jaw threads. A nut retainer member includes a first portion fixed to the body and a second portion engaging the nut. The chuck includes a plurality of recesses and a deflectable pawl biased toward and engaging the plurality of recesses. In a first state, one of the deflectable pawl and the plurality of recesses travels with the body and the other with the nut, and in a second state they travel together.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.10/834,403, filed Apr. 29, 2004, the entire disclosure of which isincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to chucks for use with drills orwith electric or pneumatic power drivers. More particularly, the presentinvention relates to a chuck of the keyless type which may be tightenedor loosened by hand or actuation of the driver motor.

BACKGROUND OF THE INVENTION

Hand, electric and pneumatic tool drivers are well known. Although twistdrills are the most common tools on such drivers, the tools may alsocomprise screw drivers, nut drivers, burrs, mounted grinding stones, andother cutting or abrading tools. Since the tool shanks may be of varyingdiameter or of polygonal cross section, the device is usually providedwith a chuck adjustable over a relatively wide range. The chuck may beattached to the driver by a threaded or tapered bore.

A variety of chucks have been developed in the art. In an oblique jawedchuck, a chuck body includes three passageways disposed approximately120 degrees apart from each other. The passageways are configured sothat their center lines meet at a point along the chuck axis forward ofthe chuck. The passageways constrain three jaws that are moveable in thepassageways to grip a cylindrical or polygonal tool shank displacedapproximately along the chuck center axis. The chuck includes a nut thatrotates about the chuck center and that engages threads on the jaws sothat rotation of the nut moves the jaws in either direction within thepassageways. The body is attached to the drive shaft of a driver and isconfigured so that rotation of the body in one direction with respect tothe nut forces the jaws into gripping relationship with the tool shank,while rotation in the opposite direction releases the grippingrelationship. The chuck may be keyless if it is rotated by hand. Variousconfigurations of keyless chucks are known in the art and are desirablefor a variety of applications.

SUMMARY OF THE INVENTION

The present invention recognizes and addresses considerations of priorart constructions and methods. In one embodiment of the presentinvention, a chuck has a generally cylindrical body having a nosesection and a tail section, the tail section being configured to rotatewith the drive shaft of the driver and the nose section has an axialbore formed therein. A plurality of jaws are movably disposed withrespect to the body and are in communication with the axial bore. A nutis rotatably mounted about the body and is in operative communicationwith the jaws so that rotation of the nut in a closing direction movesthe jaws toward the axis of the axial bore and rotation of the nut in anopening direction moves the jaws away from the axis. A generallycylindrical first sleeve is rotatably mounted about the body and is indriving engagement with the nut. The chuck also includes a tighteningindicator having a first ring received intermediate the nut and the bodyand a second ring that rotates relative to the first sleeve over alimited arc. Additionally, one of the first ring and the second ringdefines a ratchet and the other of the first ring and the second ringdefines at least one deflectable pawl biased toward the ratchet.Moreover, the first ring is rotationally coupled to the second ring inthe closing direction until the jaws clamp onto a tool shank;thereinafter, the first ring is rotationally fixed to the chuck body sothat the second ring is rotatable relative to the first ring in theclosing direction.

In another embodiment, a chuck has a generally cylindrical body having anose section and a tail section, the tail section being configured torotate with the drive shaft of the driver and the nose section having anaxial bore formed therein. A plurality of jaws is movably disposed withrespect to the body in communication with the axial bore. A nut isrotatably mounted about the body and in operative communication with thejaws so that rotation of the nut in a closing direction moves the jawstoward the axis of the axial bore and rotation of the nut in an openingdirection moves the jaws away from the axis. A generally cylindricalsleeve is rotatably mounted about the body and in driving engagementwith the nut. The chuck also has a tightening torque indicator having aplurality of equally spaced recesses that travel with one of the nut andthe body and at least one deflectable pawl that travel with the other ofthe nut and the body. The at least one deflectable pawl is biased towardand received in one of the plurality of equally spaced recesses.Movement of the at least one deflectable pawl from the one of theplurality of equally spaced recesses to an adjacent one of the pluralityof equally spaced recesses corresponds to a predetermined input torqueon the nut that results in a predetermined output gripping force betweenthe plurality of jaws.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate one or more embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendeddrawings, in which:

FIG. 1 is an exploded view of a chuck in accordance with an embodimentof the present invention;

FIG. 2 is a longitudinal view, in cross section, of the chuck shown inFIG. 1;

FIG. 3A is a partially exploded perspective view of the chuck shown inFIG. 1 with the sleeve and nut shown in a clamped position;

FIG. 3B is a partially exploded perspective view of the chuck shown inFIG. 1 with the sleeve and nut shown in a released position;

FIG. 4 is an exploded view of a chuck in accordance with an embodimentof the present invention;

FIG. 5 is a longitudinal view, in cross section, of the chuck shown inFIG. 4;

FIG. 6 is an exploded view of a chuck in accordance with an embodimentof the present invention;

FIG. 7 is a longitudinal view, in cross section, of the chuck shown inFIG. 6;

FIGS. 8A and 8B are bottom plan views of a chuck in accordance with anembodiment of the present invention; and

FIGS. 9A-9C are bottom plan views of the chuck shown in FIG. 6.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to presently preferred embodimentsof the invention, one or more examples of which are illustrated in theaccompanying drawings. Each example is provided by way of explanation ofthe invention, not limitation of the invention. In fact, it will beapparent to those skilled in the art that modifications and variationscan be made in the present invention without departing from the scopeand spirit thereof. For instance, features illustrated or described aspart of one embodiment may be used on another embodiment to yield astill further embodiment. Thus, it is intended that the presentinvention covers such modifications and variations as come within thescope of the appended claims and their equivalents.

Referring to FIGS. 1 and 2, a chuck 10 in accordance with the presentinvention includes a body 12, a gripping mechanism, generally 14, afront sleeve 18, a nose piece 20, a rear sleeve 24 and a nut 28. In theembodiment illustrated, gripping mechanism 14 includes a plurality ofjaws 26. Body 12 is generally cylindrical in shape and comprises a noseor forward section 30 and a tail or rearward section 32. An axial bore34 formed in forward section 30 is dimensioned somewhat larger than thelargest tool shank that chuck 10 is designed to accommodate. A threadedbore 36 (FIG. 2) is formed in tail section 32 and is of a standard sizeto mate with a drive shaft of a powered or hand driver, for example apower drill having a spindle. The bores 34 and 36 may communicate at acentral region of body 12. While a threaded bore 36 is illustrated, suchbore is interchangable with a tapered bore of a standard size to matewith a tapered drive shaft. Furthermore, body 12 may be formedintegrally with the drive shaft.

Body 12 defines three passageways 38 that accommodate jaws 26. Each jawis separated from each adjacent jaw by an arc of approximately 120degrees. The axis of passageways 38 and jaws 26 are angled with respectto the chuck center axis 40 such that each passageway axis travelsthrough axial bore 34 and intersects axis 40 at a common point. Each jaw26 has a tool engaging face 42 generally parallel to chuck axis 40 andthreads 44 formed on the jaw's opposite or outer surface that may beconstructed in any suitable type and pitch. Body 12 includes a thrustring member 46 which, in a preferred embodiment, may be integral withbody 12. In an alternate embodiment, thrust ring member 46 may be aseparate component from body 12 that is axially and rotationally fixedto the chuck body by interlocking tabs, press fitting or other suitableconnection means. Thrust ring member 46 includes a plurality of jawguideways 48 formed around its circumference to permit retraction ofjaws 26 therethrough and also includes a ledge portion 50 to receive abearing assembly as described below.

Body tail section 32 includes a knurled surface 52 that receives rearsleeve 24 in a press fit fashion. Rear sleeve 24 could also be retainedthrough a press fit without knurling, by use of a key or by crimping,staking, riveting, threading or any other suitable method of securingthe sleeve to the body. Further, the chuck may be constructed with asingle sleeve having no rear sleeve, for example where the power driverto which the chuck is attached includes a spindle lock feature to enableactuation of the chuck by the single sleeve when the spindle isrotationally fixed by the spindle lock.

Nut 28, which in the preferred embodiment is a split nut, defines femalethreads 54 located on an inner circumference of the nut and is receivedin a groove 56 formed in chuck body 12 proximate thrust ring member 46.A bearing washer 62 and an annular bearing cage 58 are received betweenthrust ring 46 and nut 28. Bearing cage 58 holds a plurality of balls 60that permits the nut to rotate relative to the chuck body.

Nut 28 is shown in FIG. 1 without serrations or knurling on its outercircumference. However, it should be understood that nut 28 may beformed with axially-aligned teeth, or other forms of knurling, on itsouter circumference, and its outer edges may be provided with a smallchamfer 66 to facilitate press fitting of the nut into a bore 68 offront sleeve 18. Preferably, the front sleeve is molded or otherwisefabricated from a structural plastic such as a polycarbonate, a filledpolypropylene, e.g., glass-filled polypropylene, or a blend ofstructural plastic materials. Other composite materials such as graphitefilled polymerics may also be suitable in certain environments. Asshould be appreciated by one skilled in the art, the materials fromwhich the chuck of the present invention are fabricated will depend onthe end use of the chuck, and the above materials are provided by way ofexample only.

The outer circumferential surface of front sleeve 18 may be knurled ormay be provided with longitudinal ribs 70 or other protrusions to enablethe operator to grip it securely. In like manner, the circumferentialsurface of rear sleeve 24 may be knurled or ribbed as at 72 if desired.Front sleeve 18 is press fit to nut 28 to rotationally and axiallysecure the sleeve to the nut. The press fitting of nose piece 20 to bodynose section 30 also helps to retain sleeve 18 against forward axialmovement. Nose piece 20 may be coated with a non-ferrous metalliccoating to prevent rust and to enhance its appearance. Examples ofsuitable coatings include zinc or nickel, although it should beappreciated that any suitable coating could be utilized.

Because sleeve 18 is rotationally fixed to nut 28, the sleeve's rotationwith respect to body 12 also rotates nut 28 with respect to the body,which moves jaws 26 axially within passageways 38 due to the engagementof jaw threads 44 and nut threads 54. The direction of axial movement ofjaws 26 depends on the rotational direction of sleeve 18 and nut 28 withrespect to body 12. If a tool, such as a drill bit, is inserted intobore 34, the sleeve and nut may be rotated about chuck axis 40 in aclosing direction 88 (FIG. 3A) so that jaws 26 move to a closed positionwherein jaw tool engaging surfaces 42 grippingly engage the tool.Rotation of sleeve 18 and nut 28 about axis 40 in the opposite oropening direction 90 (FIG. 3B) moves the jaws axially rearward out ofthe closed position to an open position as illustrated in FIG. 2.

Chuck 10 includes a tightening torque indicator comprising an annularring 74 and an annular ratchet 80. Annular ring 74 defines an inwardlyextending flange 76 and has pawls 78 that are connected to the ring viaspring tabs 82. Spring tabs 82 bias the pawls radially outward fromchuck axis 40 into engagement with annular ratchet 80. Annular ratchet80 defines forwardly extending tabs 84 and a plurality of teeth 83formed on an inner circumference of the main ratchet band. Each of teeth83 has a first side with a slope approaching 90 degrees and a secondside having a lesser slope, which allows pawls 78 to slip over the teethin one direction but not in the opposite direction.

Annular ring 74 is received on chuck body 12 intermediate bearing washer62 and thrust ring 46. Annular ratchet 80 is received about annular ring74 and nut 28 so that grooves 86 (FIGS. 3A and 3B) formed on the innercircumference of sleeve 18 receive respective tabs 84. The width ofgrooves 86 is larger than the width of tabs 84 so that sleeve 18 isrotatable over a limited angular distance relative to annular ratchet80.

To close the chuck from an open condition, and referring to FIG. 3A, nut28 is rotated via sleeve 18 in closing direction 88 so that jaws 26 arethreadedly moved axially forward within passageways 38. Because tabs 84sit against the driving edges of grooves 86, annular ratchet 80 rotatesin conjunction with sleeve 18. Annular ring 74 also rotates with sleeve18 since pawls 78 rotationally fix annular ring 74 to annular ratchet80. Once jaws 26 clamp onto a tool shank, however, a corresponding axialforce is increasingly exerted rearwardly through jaws 26 to nut 28. Therearward axial force is transmitted through nut 28 to chuck body 12, andin particular against thrust ring member 46. Because annular ring flange76 is intermediate bearing washer 62 and thrust ring ledge 50, axialforce is transmitted from nut 28 through annular ring flange 76 tothrust ring member 46. This increases frictional forces between annularring flange 76, bearing washer 62 and thrust ring member 46 in adirection opposite to the direction that sleeve 18 and nut 28 are beingrotated. Accordingly, the frictional forces restrain rotation of annularring 74 with respect to body member 12. Bearing 58, however, permitssleeve 18 and nut 28 to continue to rotate relative to chuck body 12 andannular ring 74 in the closing direction. Additionally, since pawls 78are deflectable and are generally disposed in alignment with the shallowslopes of the second side of teeth 83, annular ratchet 80 continues torotate with sleeve 18 relative to annular ring 74. Thus, as annularratchet 80 rotates, the distal ends of pawls 78 repeatedly ride overteeth 83, producing an audible clicking sound as the pawl ends fallagainst each subsequent tooth's second side. Pawls 78 are generallyperpendicular to the first sides of teeth 83 and do not deflect inwardto permit rotation of annular ratchet 80 in a direction opposite to 88.That is, until the jaws clamp onto a tool shank, annular ring 74 rotateswith annular ratchet 80. Once the jaws clamp onto a tool shank, annularratchet 80 rotates in the closing direction relative to annular ring 74but is blocked from rotating in opening direction 90.

To open chuck 10, and referring particularly to FIG. 3B, sleeve 18, andtherefore nut 28, are rotated in direction 90 opposite to direction 88.Because pawls 78 and ratchet teeth 83 constrain annular ratchet 80 inthe opening direction, ring 80 initially does not move, and tabs 84therefore move through grooves 86. This slight rotation of nut 28relative to chuck body 12 causes jaws 26 to retract slightly inpassageways 38 and thereby releases the axially rearward force thatfrictionally retains annular ring flange 76 between bearing washer 62and thrust ring member 46. As a result, annular ring 74 is once againrotatable with respect to the body. As the user continues to rotatesleeve 18 in opening direction 90, tabs 84 abut the sides of grooves 86so that sleeve 18 again drives annular ratchet 80 and annular ring 74.

Depending on the frictional engagement between sleeve 18 and ratchetring 80, if sleeve 18 is thereafter rotated in the closing direction,tabs 84 may rotate through grooves 86 until the tabs abut the oppositesides of the grooves, and the chuck may then be operated in the closingdirection as described above. In the presently illustrated embodiment,however, friction between sleeve 18 and ring 80 hold the sleeve and thering together in the position shown in FIG. 3B as the sleeve is rotatedin closing direction 88 (FIG. 3A) until the jaws close onto a toolshank. When this event stops rotation of ring 74, pawls 78 hold ratchetring 80 in position until grooves 86 in the still-rotating sleeve 18pass over tabs 84. When the following edges of grooves 86 engage tabs84, the sleeve again drives ring 80, and the chuck operates as discussedabove.

In the embodiment illustrated in FIG. 4, chuck body 12 has been modifiedto receive a one piece nut 28. Forward portion 30 of chuck body 12 hasbeen narrowed to allow the one-piece nut to slip over the forward bodysection into operative engagement with jaws 26 and thrust ring 46. Thatis, in assembling the chuck of FIGS. 4 and 5, annular ring 74, bearingwasher 62 and bearing retainer 58 are slipped onto chuck body 12adjacent to thrust ring 46. Next, jaws 26 are placed into respectivepassageways 38, and one-piece nut 28 is placed into abutment withbearings 60, so that the nut threads are in meshing engagement with thejaw threads.

A nut retainer 100 is received over forward body portion 30 in abutmentwith nut 28 to retain the nut in the axially forward direction. Nutretainer 100 includes a first generally cylindrical portion 102 that ispress-fit onto the body and a second frusto-conical portion 104 thatengages the nut while providing clearance for the jaws forward of thenut. Annular ratchet 80 is received about annular ring 74 so that pawls78 engage teeth 83. Front sleeve 18 is then loosely fitted over forwardbody section 30. Drive ribs 19 (shown in phantom) formed on the innercircumference of front sleeve 18 engage drive slots 29 of nut 28, andannular ratchet tabs 84 are received in grooves 86 so that front sleeve18, nut 28 and toothed ring 80 operate as described above.

A nose piece 20 is dimensioned and adapted to be press fitted onto thefront of forward body section 30 to maintain front sleeve 18 on chuck10. It should be appreciated that nose piece 20 could also be secured bysnap fit, threading, or the like. Nose piece 20 is exposed when thechuck is assembled and is preferably coated with a non-ferrous metalliccoating to prevent rust and to enhance its appearance. In a preferredembodiment, such coating may be zinc or nickel; however, it should beappreciated that any suitable coating could be utilized.

Nose piece 20 serves to maintain front sleeve 18 in position on chuckbody 10 and in driving engagement with nut 28. In addition, nose piece20 serves the dual purpose of providing an aesthetically pleasing coverfor the nose portion that inhibits rust. This provides the advantage ofan aesthetically pleasing appearance without the necessity to coat theentire chuck body 12 with a non-ferrous material.

The chuck of FIGS. 4 and 5 operates substantially the same as theembodiment of FIGS. 1 to 3. Therefore, a discussion of the operation ofthe chuck and tightening indicator will not be repeated.

FIGS. 6 and 7 illustrate an embodiment of a chuck 10 having a sleeve 18a and an alternate tightening torque indicator. Parts of chuck 10 thathave been changed from the previous embodiments have been assignednumerical labels ending with an “a”. Chucks having a single sleeve aregenerally used with drivers having a spindle lock so that the spindlecan be rotationally fixed to the driver while the sleeve is rotated inthe opening or closing direction. Spindle locks should be wellunderstood in the art. Spindle locks do not form a part of the presentinvention and are not discussed in further detail herein. It should beunderstood, however, that the chuck of the embodiment shown in FIGS. 6-9would generally be used with a power driver having a spindle lock.

Chuck 10 has a body 12, a gripping mechanism, generally 14, sleeve 18 a,a nose piece 20, a rear disc 25 and a nut 28. Gripping mechanism 14includes a plurality of jaws 26. Body 12 is generally cylindrical inshape and comprises a nose or forward section 30 and a tail or rearwardsection 32. An axial bore 34 formed in forward section 30 is dimensionedsomewhat larger than the largest tool shank that chuck 10 is designed toaccommodate. A threaded bore 36 (FIG. 7) is formed in tail section 32and is of a standard size to mate with a drive shaft of a powered orhand driver, for example a power drill having a spindle. The bores 34and 36 may communicate at a central region of body 12. While a threadedbore 36 is illustrated, such bore is interchangeable with a tapered boreof a standard size to mate with a tapered drive shaft. Furthermore, body12 may be formed integrally with the drive shaft.

Body 12 defines three passageways 38 that accommodate jaws 26. Each jawis separated from each adjacent jaw by an arc of approximately 120degrees. The axes of passageways 38 and jaws 26 are angled with respectto the chuck center axis 40 such that each passageway axis travelsthrough axial bore 34 and intersects axis 40 at a common point. Each jaw26 has a tool engaging face 42 generally parallel to chuck axis 40 andthreads 44 formed on the jaw's opposite or outer surface that may beconstructed in any suitable type and pitch.

Body 12 includes a thrust ring member 46 which, in a preferredembodiment, may be integral with body 12. In an alternative embodiment,thrust ring member 46 may be a separate component from body 12 that isaxially and rotationally fixed to the chuck body by interlocking tabs,press fitting or other suitable connection means. Thrust ring member 46includes a plurality of jaw guideways 48 formed around its circumferenceto permit retraction of jaws 26 therethrough and also includes a ledgeportion 50 to receive a bearing assembly as described below.

Body tail section 32 includes a knurled surface 52 that receives reardisc 25 in a press fit fashion. Rear disc 25 could also be retainedthrough a press fit without knurling, by use of a key or by crimping,staking, riveting, threading or any other suitable method of securingthe disc to the body.

Nut 28, which in the preferred embodiment is a split nut, defines femalethreads 54 located on an inner circumference of the nut and is receivedin a groove 56 formed in chuck body 12 proximate thrust ring member 46.A bearing washer 62 and an annular bearing cage 58 are received betweenthrust ring 46 and nut 28. Bearing cage 58 holds a plurality of balls 60that permits the nut to rotate relative to the chuck body.

Nut 28 is shown in FIG. 6 without serrations or knurling on its outercircumference. However, it should be understood that nut 28 may beformed with axially-aligned teeth, or other forms of knurling, on itsouter circumference, and its outer edges may be provided with a smallchamfer 66 to facilitate press fitting of the nut into a bore 68 ofsleeve 18 a. Preferably, the sleeve is molded or otherwise fabricatedfrom a structural plastic such as a polycarbonate, a filledpolypropylene, e.g., glass-filled polypropylene, or a blend ofstructural plastic materials. Other composite materials such as graphitefilled polymerics may also be suitable in certain environments. Asshould be appreciated by one skilled in the art, the materials fromwhich the chuck of the present invention is fabricated will depend onthe end use of the chuck, and the above materials are provided by way ofexample only.

An outer circumferential surface of sleeve 18 a may be knurled or may beprovided with longitudinal recesses 72 or other protrusions 70 to enablethe operator to grip it securely. Sleeve 18 a is press fit to nut 28 torotationally and axially secure the sleeve to the nut. The press fittingof nose piece 20 to body nose section 30 also helps to retain sleeve 18a against forward axial movement. Nose piece 20 may be coated with anon-ferrous metallic coating to prevent rust and to enhance itsappearance. Examples of suitable coatings include zinc or nickel,although it should be appreciated that any suitable coating could beutilized.

Because sleeve 18 a is rotationally fixed to nut 28, the sleeve'srotation with respect to body 12 also rotates nut 28 with respect to thebody, which moves jaws 26 axially within passageways 38 due to theengagement of jaw threads 44 and nut threads 54. The direction of axialmovement of jaws 26 depends on the rotational direction of sleeve 18 aand nut 28 with respect to body 12. If a tool, such as a drill bit, isinserted into bore 34, the sleeve and nut may be rotated about chuckaxis 40 in a closing direction 88 (FIG. 6) so that jaws 26 move to aclosed position wherein jaw tool engaging surfaces 42 grippingly engagethe tool. Rotation of sleeve 18 a and nut 28 about axis 40 in theopposite or opening direction moves the jaws axially rearward out of theclosed position to an open position as illustrated in FIG. 7.

Chuck 10 includes a tightening torque indicator comprising an annularring 74 a and an annular ratchet 80 a. Annular ring 74 a defines aninwardly extending flange 76 and has four pawls 78 that are connected tothe ring via spring tabs 82. Spring tabs 82 bias the pawls radiallyoutward from chuck axis 40 into engagement with annular ratchet 80 a.Annular ratchet 80 a defines forwardly extending tabs 84 and a pluralityof recessed grooves 83 a formed on an inner circumference of the mainratchet band. It should be understood that the chuck of the presentembodiment can function with at least one pawl, but the optimum audibleclick is achieved with between preferably three or four pawls dependingon the number of grooves 83 a. That is, the number of grooves ispreferably an equal multiple of the number of pawls so that each pawlsimultaneously engages a corresponding groove.

As described in more detail below, and similarly to the embodimentsdescribed above, ring 74 a can rotate with respect to ratchet 80 a whenthe chuck jaws tighten onto a tool. As also similar to the aboveembodiments, such relative rotation between the ring and the ratchetproduces an audible “clicking” sound as pawls 78 move from one set ofgrooves 83 a to a succeeding set. In the present embodiment, however,grooves 83 a are spread apart from each other so that the first suchaudible indicator occurs at a point at which a gripping torque appliedby the jaws to the tool has been achieved that is sufficient to securethe tool in the chuck for expected normal operation without slipping ofthe tool in the jaws. Thus, the first clicking sound following the jaws'engagement of the tool notifies the user that the desired tighteningtorque has been achieved and that the user may therefore stop tighteningthe chuck. Of course, the level of desired gripping torque might varyamong different circumstances. Once the desired grip torque is defined,however, the degree to which the sleeve should be rotated to achieve thedesired grip torque, and therefore the angular spacing between theadjacent grooves 83 a needed to provide the first audible click at thedesired grip torque, depends upon the chuck's design and construction.

Generally, for a given chuck design and construction, there exists alinear relationship between input torque applied to the sleeve and nutafter the jaws grip a tool and grip torque applied by the jaws to thetool. Thus, a given input torque can be expected to result in apredictable grip force. The tables below provide test results showingmeasured input torque and resulting output torque.

Test Results of Input Torque and Corresponding Output Torque ChuckNumber 1 Chuck Number 2 Chuck Number 3 Input Output Input Output InputOutput Torque Torque Torque Torque Torque Torque Measurement (lbs-in)(lbs-in) (lbs-in) (lbs-in) (lbs-in) (lbs-in) 1 29 42 20 32 40 50 2 32 4622 40 38 53 3 29 42 21 38 40 54 4 31 47 20 36 35 51 5 30 45 20 38 35 536 29 40 21 35 38 56 7 29 39 20 33 38 55 8 32 44 20 36 34 54 9 32 48 2036 35 55 10  31 44 20 38 35 51 Avg. 30.4 43.7 20.4 32.7 36.8 53.2

As shown above, the output gripping force of a chuck is generallyproportional to the torque exerted on the nut through the sleeve as thesleeve is rotated in the closing direction once the jaws contact thetool shank. The proportional relationship between input torque and gripforce for a given chuck depends upon design and construction factors,including but not limited to the thread pitch of the jaws and the nut,lubrication between the chuck's moving parts, finishes on the surfacesof the moving parts, the bearing system employed, the area of contactbetween abutting surfaces that move relative to each other, and theangle of the jaw passageways relative to the central axis of the body.Consequently, varying one or more of the above chuck characteristics canresult in an increase or decrease in the ratio of input torque to outputgripping force.

Thus, where the relationship between input torque and output grip forceis known for a given chuck arrangement, the desired angular spacingbetween grooves 83 a can be determined by measuring the rotation of thesleeve and nut needed to achieve an input torque that corresponds to thedesired grip force. For example, with a tool shank placed in axial bore34, sleeve 18 a may be rotated until the jaws engage the shank and thenut stops rotating relative to chuck body 12. A torque wrench is thenattached to sleeve 18 a, and the sleeve is rotated by the torque wrenchin the closing direction until the input on the torque wrench readsapproximately the target input torque. The angle between the torquewrench starting point and ending point is equal to the angular rotationthe sleeve and nut must rotate to produce the required input torque toresult in the desired output gripping force. For the chuck embodimentillustrated in FIGS. 6-7, the angular rotation is approximately 30degrees (FIG. 7). The last step is to determine the number of times themeasured angle divides into 360 degrees. In the present example, 30degrees goes into 360 degrees twelve times. Thus, annular ratchet 80 ais formed with twelve recessed grooves 83 a equally spaced about theinner circumference of the ratchet.

Of course, it is possible, and in fact likely, that the measured anglewill not divide into 360 degrees by a whole number. In that event, thenumber of grooves is preferably at most the next lowest whole number.For example, assume that the angle measured by the torque wrench toachieve the desired grip is 25 degrees. Twenty five degrees divides into360 degrees 14.4 times. At most, 14 grooves should preferably beprovided in the sleeve. Fourteen grooves provide the spacing closest tothat which corresponds to the desired input torque and gripping force.More than 14 evenly distributed grooves would result in a first clickprior to the point at which the desired input and grip torque areachieved. Fewer than 14 evenly-spaced grooves would result in the userapplying more torque than necessary to achieve the minimum desired griptorque, but such arrangements may be desirable. For example, the numberof grooves 83 a should be a whole multiple of the number of pawls 78 sothat all pawls simultaneously engage respective grooves. Thus, assume inthe above example that it is desired to have four pawls. Four does notdivide evenly into 14, and the number of grooves would preferably beadjusted downward to 12 grooves, the first whole multiple of four thatis less then 14. Thus, referring to FIG. 8A, chuck 10 has 20 equallyspaced grooves. Thus, the chuck required no more than 18 degrees ofangular rotation to result in 20 equally spaced recessed grooves onratchet 80 a. The chuck shown in FIG. 8B has 16 equally spaced grooves.Thus, the chuck required no more than 22.5 degrees of angular rotationto result in 16 equally spaced recessed grooves on ratchet 80 a.

Annular ring 74 a is received on chuck body 12 intermediate bearingwasher 62 and thrust ring 46. Annular ratchet 80 a is received aboutannular ring 74 a and nut 28 so that grooves (not shown) formed on theinner circumference of sleeve 18 a receives respective tabs 84. Thewidth of the grooves is larger than the width of tabs 84 so that sleeve18 a is rotatable over a limited angular distance relative to annularratchet 80 a.

To close the chuck from an open condition, and referring to FIGS. 7 and9A-9C, nut 28 is rotated via sleeve 18 a in closing direction 88 so thatjaws 26 are threadedly moved axially forward within the jaw passageways.Because tabs 84 sit against the driving edges of the sleeve grooves,annular ratchet 80 a rotates in conjunction with sleeve 18 a. Annularring 74 a also rotates with sleeve 18 a since pawls 78 rotationally fixannular ring 74 a to annular ratchet 80 a. Once jaws 26 clamp onto atool shank, however, a corresponding axial force is increasingly exertedrearwardly through jaws 26 to nut 28. The rearward axial force istransmitted through nut 28 to chuck body 12, and in particular againstthrust ring member 46. Because annular ring flange 76 is intermediatebearing washer 62 and thrust ring ledge 50, axial force is transmittedfrom nut 28 through annular ring flange 76 to thrust ring member 46.This increases frictional forces between annular ring flange 76, bearingwasher 62 and thrust ring member 46 in a direction opposite to thedirection that sleeve 18 a and nut 28 are being rotated. Accordingly,the frictional forces restrain rotation of annular ring 74 a withrespect to body member 12 (FIG. 9A).

Referring to FIG. 9B, however, bearing 58 permits sleeve 18 a and nut 28to continue to rotate relative to chuck body 12 and annular ring 74 a inthe closing direction. Additionally, since pawls 78 are deflectable andare generally disposed in alignment with the shallow sloped walls ofrecessed grooves 83 a, annular ratchet 80 a continues to rotate withsleeve 18 a relative to annular ring 74 a. Thus, as annular ratchet 80rotates the distal end of pawls 78 ride over the flat inner surface ofannular ratchet 80 a between adjacent recessed grooves. Referring toFIG. 9C, once the desired input torque has been applied to thesleeve/nut combination, each pawl 78 simultaneously enters acorresponding recessed groove 83 a adjacent to the starting recessedgroove, thereby producing an audible clicking sound indicating that theproper output gripping force has been achieved. That is, in theillustrated embodiment, in order for the audible click to occur, thesleeve/nut/annular ratchet combination must be rotated 30 degrees fromthe point where the jaws engaged the tool shank in order for the pawlsto move from one recessed groove to the next adjacent groove.

To open chuck 10, and referring particularly to FIGS. 9A-9C, sleeve 18a, and therefore nut 28, are rotated in an opposite direction todirection 88. Because pawls 78 and recessed grooves 83 a constrainannular ratchet 80 a in the opening direction, ring 80 a initially doesnot move, and tabs 84 therefore move through the sleeve grooves. Thisslight rotation of nut 28 relative to chuck body 12 causes jaws 26 toretract slightly in passageways 38 and thereby releases the axiallyrearward force that frictionally retains annular ring flange 76 betweenbearing washer 62 and thrust ring member 46. As a result, annular ring74 a is once again rotatable with respect to the body. As the usercontinues to rotate sleeve 18 a in the opening direction, tabs 84 abutthe sides of the sleeve grooves so that the sleeve again drives annularratchet 80 a and annular ring 74 a.

If sleeve 18 is thereafter rotated in the closing direction, frictionbetween sleeve 18 and ring 80 hold the sleeve and the ring together inthe position they were in the opening direction until the jaws closeonto a tool shank. When this event stops rotation of ring 74, pawls 78hold ratchet ring 80 in position until grooves 86 in the still-rotatingsleeve 18 pass over tabs 84. When the following edges of grooves 86engage tabs 84, the sleeve again drives ring 80, and the chuck operatesas discussed above.

It should be appreciated by those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the scope and spirit of the invention. Forexample, the tightening torque indicator shown in FIGS. 6-8 can beemployed in the dual sleeve shucks shown in FIGS. 1-5. It is intendedthat the present invention cover such modifications and variations ascome within the scope and spirit of the appended claims and theirequivalents.

1. A chuck for use with a manual or powered driver having a drive shaft, said chuck comprising: a. a generally cylindrical body having a nose section and a tail section, said tail section being configured to rotate with the drive shaft of the driver and said nose section having an axial bore formed therein; b. a plurality of jaws movably disposed with respect to said body in communication with said axial bore; c. a nut rotatably mounted about said body and in operative communication with said jaws so that rotation of said nut in a closing direction moves said jaws toward an axis of said axial bore and rotation of said nut in an opening direction moves said jaws away from said axis; d. a nut retainer member including a first portion and a second portion, said first portion being fixed to said body and said second portion being configured to engage said nut; e. a plurality of recesses, and f. at least one deflectable pawl biased toward and engaging said plurality of recesses, wherein one of said plurality of recesses and said at least one deflectable pawl travel with said nut, and the other of said plurality of recesses and said at least one deflectable pawl travels: with said body when said chuck is in a first state in which said jaws are clamped on a shank of a tool thereby causing an audible click, and with said one of said plurality of recesses and said at least one deflectable pawl when said chuck is in a second state.
 2. The chuck of claim 1, further comprising a first ring defining said recesses, wherein said first ring is rotatable with respect to said nut over a limited distance.
 3. The chuck of claim 2, further comprising a second ring defining said at least one deflectable pawl, said second ring being disposed between said nut and said body.
 4. The chuck of claim 3, wherein said body includes a thrust ring.
 5. The chuck of claim 4, said chuck further comprising a bearing located intermediate said nut and said thrust ring.
 6. The chuck of claim 5, said chuck further comprising a bearing washer located intermediate said bearing and said thrust ring.
 7. The chuck of claim 6, wherein said second ring is intermediate said bearing washer and said thrust ring.
 8. The chuck of claim 7, wherein when said chuck is in said first state, said nut imparts axially rearward force against said bearing thereby rotationally locking said second ring between said bearing washer and said body.
 9. The chuck of claim 2, wherein said plurality of recesses is formed on an inner circumference of said first ring.
 10. The chuck of claim 1, wherein when said chuck is in said first state, said nut is rotatable with respect to said body over a limited distance in said opening direction so that said jaws unclamp from the tool shank placing said chuck in said second state where said at least one deflectable pawl travels with said plurality of recesses.
 11. The chuck of claim 1, wherein when said chuck is in said first state, said nut imparts axially rearward force against said body thereby rotationally locking said one of said plurality of recesses and said at least one deflectable pawl to said body.
 12. The chuck of claim 1, further comprising at least one sleeve wherein said at least one sleeve is rotationally fixed to said nut.
 13. The chuck of claim 1, wherein said nut retainer member is press fit to said body.
 14. The chuck of claim 1, wherein said first portion of said nut retainer member is cylindrical and said second portion is frustoconically shaped. 